Pressure Systems 9022 user manual Coefficient Storage

Pressure Systems, Inc. NetScanner™ System (9016, 9021, & 9022) User’s Manual

4.6Coefficient Storage

The various calibration functions described in Sections 4.2 through 4.4 update the active offset and gain coefficients, respectively, in the module’s volatile main memory (RAM) only. These newer calibration coefficients will be lost when instrument power is turned off. The Set/Do Operating Options (‘w’) command may be used to also store these coefficients back in each transducer’s nonvolatile memory. This command’s option index = 08 will store new offset coefficients, while its option index = 09 will store new gain coefficients.

A user may read (and should verify) any new offset and/or gain coefficients after performing each calibration adjustment command (i.e., by saving coefficient data returned in a command ‘h’ or ‘Z’ response), or the Read Internal Coefficients (‘u’) command may be used to read them any time after calibration adjustment commands have been performed (see coefficient indexes cc=00 and 01 for arrays aa=01 through 10). These “adjusted” coefficients may be verified, and then saved by storing them in each transducer’s non-volatile memory with the ‘w’ command described above. Alternately, they may be verified and stored on the host computer’s secondary storage, and later restored (if necessary) with the Download Internal Coefficients (‘v’) command (same array/coefficient indexes as ‘u’).

4.7Non-volatile Parameter Storage for “non-Digitally Compensated” Pressure Sensors (9021/9022 ONLY)

4.7.1

This section describes the capability to download and store parameters to NetScanner™ System 9021 and 9022 modules for use in calibrating and/or identifying sensors that do not conform to the serial data storage and retrieval format of digitally compensated PSI 9400 sensors. When using other than digitally compensated 9400 sensors, two alternative methods are available to allow for non-volatile storage of key parameters for sensors attached to a 9021 or 9022. The first method applies when using a non-digitally compensated 9400 sensor without non-volatile memory or when using a third party sensor. This method provides the capability to calibrate sensor measurements on the NetScanner™ System module even though the sensor itself does not have the ability to store parameter data.

Commands that “download” parameters write the value into volatile memory in the module. This volatile copy of the parameter is not actually copied into non-volatile memory until the ‘w07’ command is issued. This provides the capability to test new parameters before committing them to non-volatile memory. It is important to note that the ‘w07’ command stores the entire block of non-volatile parameters for the module. The second method applies when using a non-digitally compensated 9400 sensor that has non-volatile memory.

4 - 19www.PressureSystems.com